Entangled Photons Sneak through Hole Unscathed

Luiz Carlos Ryff

Mark Buchanan

The fragile quantum state of a pair of entangled photons can be protected when the photons pass through a nanoscale hole, which may be useful in future light-based computing.

F. Zäh, Thomas Feurer

Terry B. Bollinger

When someone attempts to sneak in an observation on an entangled set of particles in the here-and-now, the quantum result looks just as if a record of that transgression was captured, sent back in time to the original generation of the entangled particles, and then rebroadcast for everyone in the future to see.

Mirko Lobino, Jeremy L. O’Brien

Richard Fitzgerald

A deeply held tenet of quantum mechanics, dating back to its infancy, is that one can't measure a system without disturbing it. That doesn't mean, however, that one can't influence the form such a disturbance takes. Over the past 25 years, researchers have been developing schemes for controlling the effects of measurements so that the properties of interest emerge unscathed. Now a group led by Serge Haroche at the Ecole Normale Supérieure (ENS) in Paris has demonstrated such techniques at the most fundamental level—detecting the presence of a single photon in a nondestructive way.